The area around and the city of Heidelberg - now known as Metropol Region Rhein-Neckar - is rich on cultural, scientific and technological sites of interest and institutions, covering several thousan years of human history.
Prehistoric relicts have been found showing that the area of Heidelberg most likely was inhabitated in pre-historic times. The remainings are amongst the oldest relicts of human/pre-human beeings in Europe. Most likely, an ancestor of the Homo Neandertaliensis was living in the area.
Historically, Celtic and Roman remainings prove the importance of the crossing of the river Neckar at this location. The Celts had around 500 b. C. a fortificated village on top of the northern hill of todays citiy. From about 100 - 300 a. C, the Romans used a wooden (later: stone) bridge and a fortress on the northern riverside.
Since 870, an abby was located on one of the hills above the northern riverside, being created near or on the remainings of the celtic village. Several small villages in the range of todays city have been named in codices from about 796 to 1192.
The raise of the city of Heidelberg started in the 12th century, when it was given to Konrad the Staufer by Friedrich I. Barbarossa in 1156. In the 13th century, the first buildings of the famous Heidelberg Castle have been created. From 14th century, the city of Heidelberg became the residence of the Duke of Palatine.
In 1386, the University of Heidelberg was founded by Karl Ruprecht I., Duke of Palatine. It is therefore the oldest University in Germany today. A continuous groth of importance followed, until Heidelberg gained reputian in the 15th century as a major center of early Humanism.
Since 16th century, the Palatine became Calvinistic, shown by the famous books "Heidelberger Katechismus" (1563) and a first complete translation of "Institutio Christianae Religionis" (1572), the main book of Johannes Calvin. A little later, Friedrich V., Duke of Palatine, created the famous "Hortus Palatinus" to provide a nice environment to his wife, Elisabeth Stuart of England. As a birthday present, he forced the construction of the "Elisabeth Gate" - it was built within one night, and can still be seen at the Castle today. In 1619, Friedrich was elected to King of Bohemia and Leader of the so-called Protestantic Union, taking part to the 30years-war. He became famous under the name "King of one Winter" and lost his kingdom in 1620. 1622 Heidelberg was conquered, the world-famous "Bibliotheka Palatina", the collection of most valuable codices and books of the university, was taken by the winners, and brought to Rome as a gift for the Pope Gregor XV.
The line of the Dukes of Palatine ended in 1685. The king of France, Louis XIV., tried to gain the area for his empire. In 1688 and 1693, Heidelberg was destroyed by French soldiers and burned down completely. Today, only a few houses exist from the time before this, namely the "Hotel zum Ritter" in the City Center. Later, the residence of Palatine was moved to the city of Mannheim nearby.
In 19th century, Heidelberg became the focus of Romantic. Poets like Friedrich Hölderlin, Achim von Arnim, Clemens Brentano and Joseph von Eichendorff where the most famous names in this period.
Industrialization was not so much to see in the city, but tourism. the numerous students of the University and the Students Corps, which are in many cases still active today, coloured allday's life.
In the 20th century, nationalistic tendencies were also present at the city. However, Heidelberg is one of only a few cities which have not been destroyed in WW2. After this war, it became the Command Center for the US Army Europe as well as the NATO.
Today, Heidelberg and the Metropolregion Rhein-Neckar is a center of life, science and technology. Some of the most important companies of Germany are located here. University and Research Centers are well-known worldwide. A brief overview on the area can be found here...
Some more detailled info can be retrieved